Grease interceptor



July 13, 1943. E. w. N. BOOSEY GREASE INTERCEPTOR Filed D60. 27, 1940INVENTOR fo n a/aM/l/fiaosey gig/aw 2'.

ATTORNEY.

Patented July 13, 1943 UNITED STATES PATENT OFFICE 8 Claims.

This invention relates to grease interceptors, the object being toprovide a new and improved form of grease interceptor of suchconstruction that an air lock is provided whereby the flow velocitythrough the interceptor is controlled and a predetermined volume of airretained within the interceptor.

It is further an object and feature of the invention to provide a newand improved construction for providing an air lock which includes anopen ended tube opening to air space at its upper end and dischargingthrough the outlet at a distance below the liquid level in theinterceptor body and the distance the tube extends below the liquidlevel is determined by the head pressure to which the inlet issubjected. By this arrangement a substantially constant liquid level isprovided under flow conditions and provides uniform flow to theinterceptor under varying flow velocity from the connected plumbingfixtures without surging. In conjunction with the air lock hereinaftermore fully decribed the outlet conduit must be vented to atmosphere andit is by this last named vent in the structure herein disclosed that thesiphcnage is prevented.

In the invention herein disclosed the lowermost point of the outletconnected to the body of the interceptor determines the normal liquidlevel therein and the inlet discharges to the interceptor body below theliquid level and into a device providing for separation of the oils andgreases from the infiowing liquid prior to discharging into the mainbody of the interceptor and thence to the outlet.

These objects and the several novel features of the invention arehereinafter more fully described and claimed and the preferred form ofconstruction by which these objects are attained is shown in theaccompanying drawing in WhiCh-- Fig. 1 is a vertical section taken online Il of Fig. 2 of a grease interceptor providing an airlock,

Fig. 2 is a plan view thereof.

Fig. 3 is a vertical section showing another form of body structure.

Fig, 4 is a vertical section of another form of interceptor wherein thecover plate is not recessed to a material degree and showing a differentform of outlet manifold and internal vent providing an air lock.

In the structure shown in Figs. 1 and 2, the body of the interceptor isindicated at I and is preferably rectangular in plan view. The bottomwall 2 of the body is formed with a recess 3 below the level of thebottom portion 2 at the outlet side thereof and a flange 4 is providedfor supporting the same upon a foundation. The bottom :2 is less inwidth than the top of the interceptor and an inclined wall 2 extendsfrom the bottom to the vertical side wall opposite the inlet. The outletconduit 5 has a horizontal portion 6 extending into the upper end of theinterceptor body on one side and to the inner end of the conduit portion6 is secured my new and improved outlet manifold l which is open at itslower end 8 to the recess 3 preferably a little below the level of thebottom 2 of the body.

This manifold l is of tubular form and in the upper end thereof issecured a vent tube 9 which extends downwardly into the manifoldterminating at a point I ll below the liquid level in the manifold andinterceptor body which level is determined by the lowermost point of theconduit portion .6. The tube 9 is sealed in the upper end of themanifold 'l as by means of a threaded plug H.

The upper end of the body is formed with an outer flange l2 and a seatl3 for the recessed cover [4 the lower edge of which is formed to engagethe seat l3 and flange l2. The upper end of the tube 9 extends to abovethe upper surface of the cover and the cover is provided with upwardlyextending portion I5 providing a recess open to the body and into whichthe upper end of the tube extends.

The inlet 16 opens into the trap body on one side thereof as shown inFig. 2 and at a point below the normal liquid level determined by theoutlet portion 6 and thus provides for discharge of liquid into theinterceptor body below the normal liquid level.

The inlet "S has a threaded horizontally positioned connector I! whichpasses through a hub l8 formed on the sideof the interceptor body andopens at its inner end into a baiile member IS on one side of the bodyas will be understood from Fig. 2. This baffle element comprises a sideplate 20 and a series of vertical plates 2| preferably integral with theplate 253 and extending at a right angle thereto.

This baffle element is supported in place against the side wall '22 ofthe body by lug elements '23 and 24 and the inner end of the plate 20rests on an inclined wall portion 2 of the body and the opposite edgeengages the vertical wall on the inlet side of the body and thus issustained in its vertical position due to the respective opposite endsof the plate 2 3 engaging the said inclined and vertical wall of thebody.

The baffle plates are spaced one from the other and the unconnected endsof these bafiie plates, opposite the ends connected with the plate 20,normally engage the wall 22 of the interceptor body. The lower edge ofthe plate 28 is inturned at 25 below the lower edge of the baffles 25providing a downwardly inclined bottom wall 25 psitioned with its upperend just beneath the inlet opening into this baiile element whichprovides an inlet chamber. The bottom wall is spaced from the lower edgeof the baffle plates and directs the flow downwardly and providesopportunity for the greases to rise between the bailles to the surfaceof the liquid in the interceptor body. This bottom wall 25 terminates at28 providing an opening 2i for the liquid to pass to the bottom of theinterceptor at the side opposite the inlet and thence to the outletthrough the manifold 3. There are some additional vertical baffles 28and 253 as shown in Fig. 1 which are spaced from the inclined wall 2 andthus the greases and oils tend to rise to the surface of the liquid andliquids of greater specific gravity flow to the bottom of theinterceptor and to the outlet. A valve controlled conduit 3i) isprovided for the drawing off of the lighter liquids while in anon-congealed state and capable of flow.

Upon discharge of liquid into the interceptor through the inlet iii theliquid level will rise somewhat above the line of connection of thecover M and ledge i3, ordinarily termed the flow level and while thiscover member may be secured in place in any desired manner and may beprovided with a packing in the groove 3] on the ledge Hi, there issometimes not a perfect seal between the cover and body. However, bypositioning the shoulder it at or a little below the flow level anyinterstices remaining between the cover and body will become sealed byfloating material on the liquid.

Upon flow of the liquids into the interceptor air and gases tend to beforced through the vent conduit ii to the outlet. Preferably the upperend of the tube 9 is a sufficient distance above the possible flow levelto prevent the lighter liquids such as oils and greases from passinginto the vent tube 9.

The structure shown in Fig. 3 has the same character of inlet and outletand bafile element at the inlet and manifold or column at the outlet asis shown in Figs. 1 and 2 and bear similar reference characters. Thestructure, however, differs in the form of the cover member and upperend of the interceptor body. The said body is provided with a preferablyintegral flange 32 which may be set in the concrete floor below thesurface and the cover member is formed with a peripheral flange 33 atits upper surface to seat on a ledge 34 of the body after the manner ofthe seating of the cover member Hi on the ledge l3 of the structureshown in Fig. 1.

The cover member 35 of Fig. 3 also has a depending fiange 35 whichcomparatively loosely fits within the upper end 31' of the interceptorbody which is of greater dimension than the main body portion and thusprovides a ledge 38 adjacent which the lower edge of the flange 36 ofthe cover member is positioned. The interstice between the flange 33 andthe upper end portion 3'! and ledge 38 is quite small in dimension andas this ledge 38 is also below the flow level in the interceptor body itwill likewise become filled with semi-solid matter and further tend toseal the cover in place. This arrangement adapts the device to besecured in a concreate floor or basin with the upper surface of thecover member practically flush with the floor.

In both the devices thus described there is provision for a dead airspace provided by the cover member which is sealed to atmosphere andfrom which accumulated air and gases may be discharged to the outletthrough the vent 9.

In many installations it is not possible to provide for the air space inthe cover member without decreasing the capacity of the interceptor andfor such installations a device may be constructed as shown in Fig. 4,in which the body of the interceptor is indicated at and the outletmanifold is indicated at 5-! and is of a different form than that shownin Figs. 1 and 3.

It is open at the bottom to a recess 52 corresponding to the recess 3 ofFigs. 1 and 3 and on one side of its upper end is provided with achamber 53 having a threaded opening in its upper wall to receive aninternally and externally threaded nut 54. A short tube 55 is threadedin the upper end of the nut to extend into the recess and a longer tube56 is threaded in the lower end of the nut and extends downwardly intolie recess 53, which is of greater diameter than the tube 55 and is openat its lower end near the bottom of the recess.

The recess 53 has an opening 38 to the upper end of the outlet manifoldEl and the tube 56 extends well below the lower edge of the opening 38.The normal liquid level in the interceptor body is above the lower edgeof the opening 38 and thus the lower end of the tube 55 is sealed to theoutlet as in a trap. The length of the tube 56 below the liquid levelmay be varied as may be determined by the head pressure at the inlet.

The manifold 59, to which the inlet discharges, is trough like in shapeand has a depending portion at at the inlet end and into which the inletconduit Si discharges. This manifold end 60 provides a wall againstwhich inflowing liquid is discharged and tends to permit the lighterliquid and oils to pass to the surface of the liquid in the manifold 59.This manifold is open at the end it! which is spaced from the verticalend wall of the manifold as shown and in the interceptor body beneaththe inlet manifold there is provided a series of spaced vertical bafileplates 62 the lower ends of which are practically in alignment parallelwith and spaced from the inclined wall of the interceptor body.

The liquid passing from the inlet manifold 59 flows beneath thesebaffles and the lighter liquids tend to pass to the surface so that theliquid is practically free from the oils and greases as it reaches thebottom of the inter:

ceptor body and passes to the outlet. The cover 63 is seated on a ledge64 at the upper end of the body in the same manner as the cover l4 inFig. 1. It is necessary in each of the forms of the interceptor hereshown to vent the outlet Patent No. 2,103,316 of Dec. 28, 1937, in thatwhile said former structure used a similar internal venting arrangementit was so constructed as to prevent siphonage of the interceptor and theinternal vent tube extended to considerable distance above the normalliquid level to prevent overfiow of grease or water to the internalvent. In this present invention the internal vent functions differentlyand the tube therefor is not required to extend any great height abovethe interceptor as the air lock prevents grease or water overflowingthrough the internal vent. When the air lock has once been establishedany additional air flowing into the interceptor from the inlet isdischarged to the sewer and does not increase the resistance of the airlock to head pressures nor does such additional air lower the liquidlevel in the interceptor.

By the arrangement herein described there is what may be termed abalanced condition existing in the interceptor practically determined bythe head pressures on the inlet and in any installation to secure thisbalanced condition the internal vent tube is extended to a distancebelow the liquid level in the interceptor sufficient to resist the headpressures. Under this condition inflowing liquid which tends to increasethe volume of liquid in the interceptor body will flow directly to theoutlet from the inlet manifold without material change in the level ofthe liquid in the body. The air accompanying the inflowing liquid risesto the surface of the liquid in the air space above the liquid leveluntil the air pressure is suflicient to break the seal of the internalvent tube and pass to the outlet through the tube 9 of Figs. 1, 2 and 3or the tubes 55, 56 of Fig. 4.

This arrangement of parts herein described therefor is a distinctdeparture in function and operation from structures heretofore known asthe practice heretofore has been to so construct the interceptor with aninternal vent adapted to prevent siphonage. In this present structuresiphonage is prevented by means of a vent to atmosphere directly openingto the outlet and the internal vent as herein disclosed tends to at alltimes maintain constant volume of liquid in the interceptor and under asubstantially constant pressure as any increase in air pressure causes adischarge of excess air to the outlet. Therefore surging of the liquidwithin the interceptor body due to velocity of inflowing liquid isavoided.

It is further desirable that the main grease retaining chamber be freefrom bailies or obstructions to flow from the point of discharge to themain chamber to the outlet. The baflle element [9 of Figs. 1, 2 and 3 isat one side of the main chamber and the baffle plates 62 of Fig. 4 arealso all positioned at one side of the main chamber above the inclinedwall on the side of the chamber opposite the inlet. It is also pointedout that the inlet can conveniently be placed on the left side of theoutlet rather than on the right side as shown as may be found desirablein some installations.

To maintain the described condition of operation most effectively it isdesirable that the valve 33 be opened at least daily to withdraw thefloating greases and oils from the surface of the liquid while in liquidcondition, otherwise the air space would eventually become decreased toa detrimental extent through solidification of the greases.

A major feature of the invention resides in the provision of a greaseinterceptor having means associated with the outlet adapted to resisthead pressures to which the liquid is subjected by flow through theinlet to thereby maintain a substantially constant liquid level in theinterceptor body under varying velocities of flow of liquid thereintofrom the inlet.

Having thus fully described my invention, its utility and mode ofoperation, what I claim and desire to secure by Letters Patent of theUnited States is:

1. In a grease interceptor, a chambered body having an inlet openingthereto below the normal liquid level therein, an element within thebody providing a secondary chamber into which the inlet directlydischarges, said secondary chamber having a downwardly inclinedbottomwall provided with an opening to the body opposite the inletopening, an outlet connected with the body and positioned to determinethe normal liquid level therein, a manifold within the body comprising aconduit open at its lower end to adjacent the bottom of the body andopening above its lower end to the outlet, a vent tube in the upper endof the manifold opening to the space in the body above the liquid leveltherein and extending into the manifold to below the liquid level in thebody, the upper end of the conduit being otherwise closed to the body.

2. In a grease interceptor, a chambered body having an inlet openingthereto below the normal liquid level therein, an element within thebody providing a secondary chamber into which the inlet directlydischarges, said secondary chamber having a downwardly inclined bottomwall provided with an opening to the body opposite the inlet opening, anoutlet connected with the body and positioned to determine the normalliquid level therein, a manifold within the body at the inlet endcomprising a vertical conduit open at its lower end to adjacent thebottom of the body and opening above its lower end to the outlet, a venttube in the upper end of the manifold opening to the space in the bodyabove the liquid level therein and extending into the manifold to belowthe liquid level in the body, the upper end of the vertical conduitbeing otherwise closed to the body.

3. In a grease interceptor, a chambered body having an inlet openingthereto on one side below the normal liquid level therein, an elementproviding a secondary chamber into which the inlet directly discharges,spaced vertical baffle plates in said element tending to causeseparation of the liquids of less specific gravity from the inflowingliquid, said secondary chamber having a downwardly inclined bottom wallprovided wtih an opening to the body adjacent the side thereof oppositthe side through which the inlet discharges, an outlet connected withthe body on the inlet side and positioned to determine the normal liquidlevel therein, a manifold element comprising a conduit open at its lowerend to the body at a point below the outlet from the secondary chamberand on the same side of the body as that to which the inlet opens, avent tube in the upper end of the conduit opening at one end to the bodyabove the normal liquid level therein and extending into the manifoldand opening thereto at a point below the normal liquid level in thebody.

4;. In a grease interceptor, a chambered body having an inlet conduitopenin thereto on one side thereof below the normal liquid leveltherein, the said bod having its upper end above the liquid leveltherein, a cover member positioned on the top of the said body andrecessed to provide a chamber for air and gas above the liquid level inthe body, an element providing a secondary chamber to which the inletconduit discharges, said chamber having a downwardly inclined bottomwall provided with an opening for discharge of liquid to the bodychamber at a point distant from the inlet, the wall of the body againstwhich the liquid discharges being inwardly and downwardly inclined tocause the liquid to flow towards the inlet side of the body, an outletconduit connected with the body and positioned to determine the normalliquid level therein below the line of contact of the cover with thebody, a manifold the inlet side of the body to which the outlet conduitopens comprising a vertical conduit open to the bottom of the body belowthe point of discharge of inflowing liquid from the secondary chamber, atube in the upper end of the said vertical conduit opening at its upperend to the air and gas space provided by the cover and extending intothe vertical conduit to a point below the point of connection of theoutlet conduit therewith, and baflle means within the secondary chamberproviding for separation of the material of lesser specific gravity fromhat of greater specific gravity whereby the material discharging fromthe secondary chamber to the outlet manifold is freed of oils andgreases.

.5. In a grease interceptor, a chambered body having an inlet openingthereto on one side thereof below the normal liquid level therein, thesaid body having its upper end above the flow level therein, a covermember positioned on the top of the said body and recessed to providefor a chamber for air and gas above the liquid level in the body, anelement providing a secondary chamber to which the inlet conduitdischarges, said chamber having an opening at the end opposite the inletfor discharge of liquid to the body proper at a point distant from theinlet, the wall of the body against which the liquid discharges beinginwardly and downwardly inclined to cause the liquid to fiow toward theinlet side of the body, an outlet conduit connected with the body andpositioned to determine the normal liquid level therein, a manifold towhich the outlet conduit opens comprising a vertical conduit open to thebottom of the body below the point of discharge of inflowing liquid fromthe secondary chamber, a tube in the upper end of the said verticalconduit opening at its upper end to the air and gas space provided bythe cover and extending into the vertical conduit to a point below thepoint of connection of the outlet conduit therewith, and bafile meanswithin the secondary chamber providing for separation of the material oflesser specific gravity from that of greater specific gravity wherebythe material discharging from the secondary chamber to the outletmanifold is freed of oils and reases, and manually controlled meansproviding for withdrawal of the liquid of less specific gravity from theinterceptor body.

6. In a grease interceptor, a. chambered body having an inlet conduitopening thereto on one side thereof below the liquid level therein, a removable element within the body providing a secondary chamber into whichthe inlet directly discharges, said secondary chamber having an openingfor discharge of liquid to the bottom of the body at a point distantfrom the point of discharge thereto from the inlet conduit, baflle meansin said secondary chamber providing for separation of oils and greasesfrom infiowing liquid prior to discharge thereof through the saidopening of the secondary chamber, an outlet conduit connected with thebody and arranged to determine the normal liquid level therein, amanifold in the body connected to the outlet comprising a verticalconduit opening to the body adjacent its bottom, a vent means comprisinga tubular element secured in the upper end of the outlet manifold withits upper end above the liquid level in the body and extending into thevertical conduit to a point below the liquid level, the upper end of thebody being at about the liquid level and a cover member fitting the topof the body and recessed to provide air and gas space above the liquidlevel to which the upper end of the vent tube is open.

'7. In a grease interceptor, a chambered body having an inlet openingthereto on one side below the normal liquid level therein, a removableelement within the body providing a secondary chamber into which theinlet directly discharges, said secondary chamber having an opening fordischarge of liquid to the bottom of the body at a point distant fromthe inlet, bafiie means in said secondary chamber providing forseparation of oils and greases from infiowing liquid prior to dischargethereof through the said opening of the secondary chamber, an outletconduit connected with the body and arranged to determine the normalliquid level therein, a manifold in the body connected to the outletcomprising a vertical conduit opening to the body adjacent its bottom, avent means comprising a tubular element secured in the upper end of theoutlet manifold with its upper end above the liquid level in the bodyand extending into the vertical conduit to a point below the liquidlevel, the upper end of the body being at about the liquid level and acover member fitting the top of the body and recessed to provide air andgas space above the liquid level to which the upper end of the vent tubeis open, said cover member having a secondary recess therein extendingto above the cover member and into which the upper end of the vent tubeopens.

8. In a grease interceptor, an outlet arranged to determine the liquidlevel therein and a chambered body having an inlet opening thereto belowthe liquid level therein, a removable element within the body providinga secondary chamber into which the inlet directly discharges, saidsecondary chamber having an opening to the bottom of the body at a pointdistant from the inlet, means in the secondary chamber providing forseparation of oils and grease from the inflowing liquid prior todischarge through the said opening of the secondary chamber, the upperend of the body being above the liquid level therein, a cover member forthe body, means providing for discharge of air and gases from the upperend of the body comprising a vent tube extending to above the covermember at its upper end and at its lower end discharging to the outletat a point below the normal liquid level in the body, said cover memberhaving a chamber extending thereabove open at its lower end to the upperend of the body and into which the said vent tube extends.

EDWARD W. N. BOOSEY.

